<?php // $Id: format.php,v 1.10.4.1 2007/11/02 16:21:08 tjhunt Exp $

// Based on default.php, included by ../import.php
/**
 * @package questionbank
 * @subpackage importexport
 */

require_once("$CFG->libdir/xmlize.php");

class qformat_examview extends qformat_default {
	
	var $qtypes = array(
		'tf' => TRUEFALSE,
		'mc' => MULTICHOICE,
		'yn' => TRUEFALSE,
		'co' => SHORTANSWER,
		'ma' => MATCH,
		'mtf' => 99,
		'nr' => NUMERICAL,
		'pr' => 99,
		'es' => 99,
		'ca' => 99,
		'ot' => 99,
		'sa' => ESSAY
		);
	
	var $matching_questions = array();

	function provide_import() {
		return true;
	}
	
	/**
	 * unxmlise reconstructs part of the xml data structure in order
	 * to identify the actual data therein
	 * @param array $xml section of the xml data structure
	 * @return string data with evrything else removed
	 */
	function unxmlise( $xml ) {
		// if it's not an array then it's probably just data
		if (!is_array($xml)) {
			$text = s(addslashes($xml));
		}
		else {
			// otherwise parse the array
			$text = '';
			foreach ($xml as $tag=>$data) {
				// if tag is '@' then it's attributes and we don't care
				if ($tag!=='@') { 
					$text = $text . $this->unxmlise( $data );
				}
			}
		}

		// currently we throw the tags we found
		$text = strip_tags($text);
		return $text;
	}
	
	function parse_matching_groups($matching_groups)
	{
		if (empty($matching_groups)) {
			return;
		}
		foreach($matching_groups as $match_group) {
			$newgroup = NULL;
			$groupname = trim($match_group['@']['name']);
			$questiontext = $this->unxmlise($match_group['#']['text'][0]['#']);
			$newgroup->questiontext = trim($questiontext);
			$newgroup->subchoices = array();
			$newgroup->subquestions = array();
			$newgroup->subanswers = array();
			$choices = $match_group['#']['choices']['0']['#'];
			foreach($choices as $key => $value) {
				if (strpos(trim($key),'choice-') !== FALSE) {
					$key = strtoupper(trim(str_replace('choice-', '', $key)));
					$newgroup->subchoices[$key] = trim($value['0']['#']);
				}
			}
			$this->matching_questions[$groupname] = $newgroup;
		}
	}
	
	function parse_ma($qrec, $groupname)
	{
		$match_group = $this->matching_questions[$groupname];
		$phrase = trim($this->unxmlise($qrec['text']['0']['#']));
		$answer = trim($this->unxmlise($qrec['answer']['0']['#']));
		$answer = strip_tags( $answer );
		$match_group->subquestions[] = $phrase;
		$match_group->subanswers[] = $match_group->subchoices[$answer];
		$this->matching_questions[$groupname] = $match_group;
		return NULL;
	}
	
	function process_matches(&$questions)
	{
		if (empty($this->matching_questions)) {
			return;
		}
		foreach($this->matching_questions as $match_group) {
			$question = $this->defaultquestion();
			$htmltext = s(addslashes($match_group->questiontext));
			$question->questiontext = $htmltext;
			$question->name = $question->questiontext;
			$question->qtype = MATCH;
			$question->subquestions = array();
			$question->subanswers = array();
			foreach($match_group->subquestions as $key => $value) {
				$htmltext = s(addslashes($value));
				$question->subquestions[] = $htmltext;

				$htmltext = s(addslashes($match_group->subanswers[$key]));
				$question->subanswers[] = $htmltext;
			}
			$questions[] = $question;
		}
	}
	
	function cleanUnicode($text) {
		return str_replace('&#x2019;', "'", $text);
	}

	function readquestions($lines) {
		/// Parses an array of lines into an array of questions,
		/// where each item is a question object as defined by
		/// readquestion().

		$questions = array();
		$currentquestion = array();
		
		$text = implode($lines, ' ');
		$text = $this->cleanUnicode($text);

		$xml = xmlize($text, 0);
		if (!empty($xml['examview']['#']['matching-group'])) {
			$this->parse_matching_groups($xml['examview']['#']['matching-group']);
		}
		
		$questionNode = $xml['examview']['#']['question'];
		foreach($questionNode as $currentquestion) {
			if ($question = $this->readquestion($currentquestion)) {
				$questions[] = $question;
			}
		}
		
		$this->process_matches($questions);
		return $questions;
	}
	// end readquestions
	
	function readquestion($qrec)
	{
		
		$type = trim($qrec['@']['type']);
		$question = $this->defaultquestion();
		if (array_key_exists($type, $this->qtypes)) {
			$question->qtype = $this->qtypes[$type];
		}
		else {
			$question->qtype = null;
		}
		$question->single = 1;
		// Only one answer is allowed
		$htmltext = $this->unxmlise($qrec['#']['text'][0]['#']);
		$question->questiontext = $htmltext;
		$question->name = shorten_text( $question->questiontext, 250 );
		
		switch ($question->qtype) {
		case MULTICHOICE:
			$question = $this->parse_mc($qrec['#'], $question);
			break;
		case MATCH:
			$groupname = trim($qrec['@']['group']);
			$question = $this->parse_ma($qrec['#'], $groupname);
			break;
		case TRUEFALSE:
			$question = $this->parse_tf_yn($qrec['#'], $question);
			break;
		case SHORTANSWER:
			$question = $this->parse_co($qrec['#'], $question);
			break;
		case ESSAY:
			$question = $this->parse_sa($qrec['#'], $question);
			break;
		case NUMERICAL:
			$question = $this->parse_nr($qrec['#'], $question);
			break;
			break;
			default:
			print("<p>Question type ".$type." import not supported for ".$question->questiontext."<p>");
			$question = NULL;
		}
		// end switch ($question->qtype)
		
		return $question;
	}
	// end readquestion
	
	function parse_tf_yn($qrec, $question)
	{
		$choices = array('T' => 1, 'Y' => 1, 'F' => 0, 'N' => 0 );
		$answer = trim($qrec['answer'][0]['#']);
		$question->answer = $choices[$answer];
		$question->correctanswer = $question->answer;
		if ($question->answer == 1) {
			$question->feedbacktrue = 'Correct';
			$question->feedbackfalse = 'Incorrect';
		} else {
			$question->feedbacktrue = 'Incorrect';
			$question->feedbackfalse = 'Correct';
		}
		return $question;
	}
	
	function parse_mc($qrec, $question)
	{
		$answer = 'choice-'.strtolower(trim($qrec['answer'][0]['#']));
		
		$choices = $qrec['choices'][0]['#'];
		foreach($choices as $key => $value) {
			if (strpos(trim($key),'choice-') !== FALSE) {
			   
				$question->answer[$key] = s($this->unxmlise($value[0]['#']));
				if (strcmp($key, $answer) == 0) {
					$question->fraction[$key] = 1;
					$question->feedback[$key] = 'Correct';
				} else {
					$question->fraction[$key] = 0;
					$question->feedback[$key] = 'Incorrect';
				}
			}
		}
		return $question;
	}
	
	function parse_co($qrec, $question)
	{
		$question->usecase = 0;
		$answer = trim($this->unxmlise($qrec['answer'][0]['#']));
		$answer = strip_tags( $answer );
		$answers = explode("\n",$answer);
		
		foreach($answers as $key => $value) {
			$value = trim($value);
			if (strlen($value) > 0) {
				$question->answer[$key] = addslashes($value);
				$question->fraction[$key] = 1;
				$question->feedback[$key] = "Correct";
			}
		}
		return $question;
	}

	function parse_sa($qrec, $question) {
		$feedback = trim($this->unxmlise($qrec['answer'][0]['#']));
		$question->feedback = $feedback;
		$question->fraction = 0;
		return $question;
	}
	
	function parse_nr($qrec, $question)
	{
		$answer = trim($this->unxmlise($qrec['answer'][0]['#']));
		$answer = strip_tags( $answer );
		$answers = explode("\n",$answer);
		
		foreach($answers as $key => $value) {
			$value = trim($value);
			if (is_numeric($value)) {
				$errormargin = 0;
				$question->answer[$key] = $value;
				$question->fraction[$key] = 1;
				$question->feedback[$key] = "Correct";
				$question->min[$key] = $question->answer[$key] - $errormargin;
				$question->max[$key] = $question->answer[$key] + $errormargin;
			}
		}
		return $question;
	} 
	
}
// end class

?>
